Ethyl cellulose-coated textile fabric



y 1950 w. w. KOCH 2,507,107

ETHYL CELLULOSE-COATED TEXTILE FABRIC Filed Aug 1, 1945 INVENTOR.

Patented May 9, 1950 UNITED STATES PETENT OFFICE William .W. Koch, Wilmingtn,"Del., assignor to Hercules. .Powder Company, Wilmington, De 1 a corporation of "Delaware Application Augustl, 1945, Serial No. 608,174

9=Qlaims. 61, 117-186) 1 This invention relates to improved textile coatings and more particularly to textiles coated with oel olos ethe saidzooa e tex ilesrheiheeap t ofre aio ne hei fiexih y-atlo t ven u es ndo re aini ir. t a tioizors outl loo ns th eh tempera u es.

It. :is e erally tha la quers o ot h ns a fi mormi poly. o -Wh the elasticized or-unp st oiz W l 121, entextil eh oswh h lac e pe trat s t o1oth .u l. th p ooo t ono fi m for e .i t o-Je que i very ow or u l s t emo ntoi eo ids rzli o h lo h, is likewise low. On the .other hand, textile tabr-i s wetted with ahigh boiling liquid, such asan oil or other type of plasticizer, possesses a pleasing drape and handle free of papery stiffness and rattle.

Nitrocellulose coatings. which satisfy to, a. greater or less degree the requirements inthese regards have been known for some time; textiles so coated generally'being termed artificial leather. I-Iowever, nitrocellulose has certain in:- herent drawbacks as ;a textile coating, especially where the coated textile is eventually used for m it purpo s uch as ntitle en oo erines. raincoats, etc. These. drawbacks include, among others, inflammability and unsatisfactory flexiloility atlow p ratures.

Textiles coa d wi h ethyl c ll lose have been prepared, but there, have been. a number of ob.- ieo ionable ieatur wh ch have m ted h ir utility. Poor adhesion has been encountered with numerous formulations, in addition to shift ening and poor handle, and particularly. blocking at elevated temperatures. Furthermore, pig: menting the coatings caused embrittlement which led to cracking. In aneffiort to prevent stiffening and cracki the plasticizer content has'been ings for textiles is that of exudation of plasti cizers, particularly mineral or vegetableoils, from the usual types of cellulose ether coatings when.

the-ether plasticizer ratio'is'lessthan aboutlzl.

Alternatively, in some cases, extreme stickiness under warmth has resulted,

Now, in accordance with this invention, the shortcomings of the-priorart have been substantially eliminatedby providing a-textilefabric with a c m t o o hr ty es. o comp s ons: Eirst, a wetting coat, which is a highly plasioi od c u s ether composition; second, a

toughening-coat,"'which'is'a cellulose ether compo it on mewha les hi hly plasticiz d-;- and third, a sealing-coat, which comprises a celluo e other o a substi ution type which will not time maybe pigmented. The sealing coat contains a cellulose ether having a relatively low ol s t t oh enemascontain-Matt n .a ent.

heorow naetco nnaoyine.thisspeoifioe ionis a cross-sectional representation of the special re.-. lationships of a typical textile fabric coated with the three types of compositions in accordance with this invention. Fabric composed of threads 4 and 5 has its interstices substantially closed by V a wetting coat 3'; Superimposed on the wetting coat is a layer or coating'z which maybe referred to ,as thetoughening coat. The uppermost coat is the sealing coat *I. It will be appreciated that each layer, --may be the result of application of several coats of: composition,

Various embodiments of theinvention are illus-. trated by the following specific examples: Table 1 contains '12 examples of Wettin coats whifih may be'applied to .thextextile fabric to fill the .in-. te s e 'thereoi- TomeZo h a n 18 amp s. f-toughening 051 which are applied over. the wetti g oat Tabl .3 how three sea g coat compositions. Ffinally 'lable 4. gives 17 of the bestcombinations of the .coats described in Tables ,2. snot- TABLEl W n co ts "Example N M, i l 2 3 4 5 6 7 8 9 10 ll 12 Ethyl cellulose, 47.5 ethoxyl, lOO cp. vi scosity-.- 30 4 30 3 0 30 30 Chlorinated dipheny y V I Bodied castor oil, 200 seconds Engler viscosity.. '1 1 Bodied castor oil, 400 seconds Englerviscositm-n v i Bodied castor oil, 1500 seconds Engler viscosit 45 Rawjcastorioil. 2 5, 7 I 70 '30 00mm H Y v Hydrogenated methyl ahie'fafe 50 Olive drab p nt i l2. 5 v .i. r i 7. 5 12. 5 15 15 Xylene... H 200 .0 150 Bntannl' 90 90- 90 50 I 40 90 60 60 Solvesso #2 (a hydrogenated petroleum iraction); V 7.-. ;l25 2,09, N

TABLE2 Touyhening coats ExampleNo 13 14 15 1o 17 18 19 2o 21 22 23 24 25 Ithyl c ellulose, 47.5 ethoxyl, 100 cp. viscosity 50 50 50 40 40 40 40 40 50 50 50 40 0111 m Bodied castor oil, 200 seconds Englcr viscosity 25 30 30 Bodied castor oil,400 seconds Engler viscosity 25 60 30 Bodied castor oil, 1500 seconds Engler viscosity- 25 l Raw castoroil 25 25 25 30 30 30 50 50 50 30 Hydrogenated methyl ebicfafe Olive drab pigment 12.5 12.5 12.5 15 15 15 15 15 15 7.5 12.5 15 Xylene 250 250 250 200 200 200 200 150 250 250 14c Bnmnnl 100 100 100 so so so 85 35 so 60 100 100 so Solvesso #2 200 200 TABLE 3 The coated cloth had a soft handle, good drape, and was highly flexible. It was suitable for such Sealing was a use as raincoat cloth. At -20 0., flexibility was satisfactory, while after heating at 180 F. Example No 2s 27 2s for 30 minutes, as described hereinafter, there was no evidence of blocking. Ethyl cellulose, 45% ethoxyl, 100 cp. viscosity-. 30 While the examples show the use of ethyl 3 5553 353 g cellulose in specific embodiments of the inven- Di ihenylamine 0. 23 tion, and while this is the preferred cellulose ggtgf gl 1 100 100 25 ether for carrying out the invention, other cel- Solvesso #2 250 lulose ethers may be used. These include other alkyl ethers such as methyl, propyl or butyl; TABLE 4 Best combinations of above coatings Combination-Example No 29 so 31 a2 a3 a4 35 so 37 as 39 4o 41 42 43 44 45 Wetting Coat-Example Nol 2 2 3 3 3 4 4 5 6 7 8 0 10 10 ll '12 Toughening Coat-Exam is No 13 14 1a 13 15 21 1o 1o 17 19 20 22 23 23 24 25 25 Sealing Coat-Example 0-.." 2s 2s 2s 2s 2s 27 27 2s 27 2s 2s 28 2s 2s 28 27 27 Example 46 shows the application to a textile fabric of compositions given under Examples 2, 18, and 27.

Example 46 A wetting coat dope of the composition under Example 2 of Table 1 was prepared by mixing the ingredients in a closed vessel equipped with a slow-moving agitator until a smooth dope was obtained. The pigment had previously been dispersed ona three-roll mill in a portion of the plasticizer in the ratio of 1 part pigment to 2 parts plasticizer. All composition figures in these examples are in parts by weight. The wetting dope obtained was then applied to cotton cloth weighing 4 ounces per yard by use of a doctor knife coater. Solvents were removed by drying at 100 C. Application had been adjusted so that 1.3 ounces of the dried composition were applied to 1 square yard of cloth. This amount was sufiicient to fill the interstices of the cloth but not to. leave any surface coating thereon.

A toughening coat dope of the composition under Example 18 of Table 2 was prepared in The toughening coat dope was applied. to the filled cloth with a doctor knife coater so' as to deposit 1.3 ounces of solids in a continuous coating per square yard of the cloth; Solvents were removed as above.

A sealing coat dope of the composition under Example 27 of Table 3 was prepared by dissolving the ethyl cellulose in the solvent and adding the fiatting agent and stabilizer during the latter stages of mixing. This was applied to the filled and coated cloth with a doctor knife coater adjusted to give a dry coating of 0.4 ounce per yard of cloth. Solvents were removed in the same mannerasbefore. 4

the same manner as the wetting coat dope above.

such as hydroxy-alkyl and carboxy-alkyl cellu-" loses will ordinarily require an insolubilizing treatment, preferably after application to the textile.

The cellulose ethers for each coat must be carefully chosen so that the plasticizers used therewith in the wetting and toughening coats will not penetrate through the sealing coat. Thus, when the multiple coatings comprise ethyl cellulose as the cellulose ether, it is preferred that the ethoxyl of the cellulose ether be between about 40.0 and about 52.0% in the wetting coat and between about 44.5 and about 52% in the toughening coat, while that of ethyl cellulose in the sealing coat is preferably between about 40.0 and about 45.5%.

It has been found that the substitution of the cellulose ether in the wetting coat is not so important as the difierence in substitution between the cellulose ether of the toughening coat and that of the sealing coat. This difierence in substitution of the latter two coats is to be such as Y to prevent appreciable migration of the plasticizer of the middle coat into or through the sealing coat. The sealing coat cellulose other will be less soluble in the plasticizer of the toughening coat than the cellulose ether of the toughening coat and may, in fact, be incompatible with said plasticizer.

To obtain the-optimum conditions in this respect when the cellulose ether. is ethytcellulose,

theethoxyl .of the sealing coat :is atleastLS%--.1ess:- than that of the ethyl cellulose in the toughening.

coat. Preferably, a. relatively: highethoxyl is used for theitoughening coatin order; to obtain maximum flexibility and compatibility withplas ticizers;

- It.-. will be noted that thesealing. coat-thus comprises ethyl cellulose which has:only a limited" compatibility.- with plasticizers... such; as; mineral oils or: vegetable; oils;- in the sense; that .theyywillrepel said plasticizers back into thegmoreucome patibletypes of ethyl. cellulose in: the: wetting and toughening coatsinstead of. allowing. them. to penetrate through and exude from the. sealing. coat, or mix: with. and. cause.v blockingof; said coat.

The. viscosities ofpthecellulose. ethersto be used.

in. the: three. types of; coats may: vary within wide limits- The, dope must; have a: composite; viscosity suitable for application withpa particulartype of coatingv apparatus.

Ithas beenjoundthat-thei viscosity of the eellulose'etheryin the wettingzand toughening coats.

may vary;betweenabout 5.0:.and-about 300centipoises,, and,preferably isabout 1'00 centipoises.

The viscosity of the cellulose ether in the sealing,

coatmay vary. from about IDOcentipoisesto about 500 centipoisesandpreferablyis about 300 centinoises.

The present invention permits the employment,

asjtextileg-coatings, of highly plasticized cellulose: ethers; in. the. wetting-; and, toughening. coats.

shown by; Examples 26, 27, and 28 in Table 3, it isa preferred practice to use no plasticizer what: ever in the=sealingi coat. However, a limited amount of plasticizer may be used .therein, but. thecellulose ether1plasticizer. ratio. should be;

greater than about 3:1.

A wide range of plasticizers may be used in carrying out the present invention. by Examples 1-25, chlorinated diphenyl hydro-.

genated methyl abietate, corn oil, raw castor 011,-.

and bodied castor oil are. especially. suitable. Other plasticizerswhich may. be used include mineral oils such as vNujol or. refined. types of. lubricating oil; other vegetable oils such as cottonseed, linseed, orsoybean oils; fatty acids such as oleic or stearic acids; amides such as paratoluene-sulfonamide; phosphate esters such as tricresyl phosphate, or triphenyl phosphate, phthalate esters such as dimethyl'phthalate, or. dibutyl phthalate; and carbohydrate derivatives such as mannitol propionate, or= sorbitol propionate.

The plasticizers preferred-above others; in car rying out thetpresent inventionare chlorinated diphenyhraw castor oil, and lightly-bodied castor: oil.; When castor. oils. are; the plasticizers used, it is apreferred. practice toruse mixturesof raw and lightly-bodied varieties; Raw castor oil promotes flexibility. of. the. coatings while the bodied oil promotes adhesion.

The raw vegetable. oilsmay be bodied by various" meanssuch as. heating or oxidizing. Oxidation isusuallyaccompaniedfby polymeriza- As shown tion and sincezhigh'ly:polymerizedtoilszimpartzlowr temperature brittlenesmto a. coating; itiis pre.-: ferred: to...utilize onlys-such oxidizedmils as have: been polymerized :to :.a;relatively. mildidegree. By:

the aforesaid term, vegetable oils polymerizediby: other means .are also included, for example; by heat. The :term vegetable: oil also includes-mixturesofxthejvegetable. oils mentioned hereinbeforee However, it :is. preferred' practiceato iutilizeiuraw: castor oil or castor oil which;hasbeenslightly.

polymerized; by" oxidation; as the. vegetable; oil softener of this invention.

This softener may; be; for: example, castor oil.

which has: been; oxidized and; at. the same time, polymerized :to -such z-an extent as to change. its. viscosity from the; original 130; seconds Engler to 400; seconds Engler; such asthe; oil known as.

Bakers Pale No;..4'i'Castor;Oil. Another useful: type of oil for rtheypnrposeof the .present inven-:-.

tion has receiveda: lighter1bodying:;treatment to;

give a-viscosity of :about200 seconds :;.rEngler., such as the castor oil-known. as Bal ersi1=2AC.-;OilJ" Oils havinga higher. degree of: bodyingfgare also useful forthis invention.v A-specific example-of.

such an oil is known as Bakerfs .'#16:-Pale.- Blown Castor Oil, havingan Engler viscosity of about.-

1500 seconds viscosity; v

Pigments other. than the olive. drab. pi ment,- shown in the examples,-, ,mayg'be. usedv in the;coatings. of thepresent invention... Asshownby the;

examples, it is;- a preferredpractice. to apply. the pigment in the. wetting; and toughening; coats, while. the sealing. coat .ispreferably, a. clear. one.

Although the preferredcellulose. ether; pigment. ratio. range'is between. about. 4:1.to about 2:1 in the wetting coat, saidratio. may vary from about;

6:1.to about 3:2.., As shown. by. Examples. 13-25,, the preferred cellulose ether pigment ratio rangev in the toughening. coat .is from about 6.121 to about 2.7 1, theratio rangemayvary from about.

8:1 to about. 2.1.. Although. it isapre'ferred practice to omit pigment'r'rom. the sealing coat,

cellulose ether: pigment. ratiosgreater than about.

4:1 are permissible. Flatting agents other than the zinc stearate shown. in Example 27 include diatomaceous earth, magnesium carbonate, and aluminum stearate.

It'will be understood that there may be considerable variation in the weight .of coatings applied for various purposes. For raincoat material.

made of a fabric such as that shown in Example 46, it is preferred that the wetting and toughening coats weigh from about 1.2 to about 1.5'ounces per square yard'and thatv the sealing. coat weigh from about 0.3"to about 0.5 ounce per square yard.

However, coatedlfabrics may be made according to the present invention bearing coating weights commensurate with their. intended use. It is preferred practice to apply a sealing coat of. con- I siderably less weight than the. wettingor toughening coats so as toavoid stiffening.

While the examples show the application of the several coats. to theafabricuin the-form of dopes, it is within the contemplation of. this in-- vention that: said: coats be applied as hot melts.

by use of a roll mill, doctor'knife, or calender stack. This hotmeltmethod would beparticularly suitable for thewetting; and: toughening. coats, since they contain large amounts of plasti cizer. If applied indope form,- the consistency oi-the. dope may beiadjusted for spray, brush, or. doctor knife application:

thenextis applied.

It is also within.thacontemplation ofithis in Solvents will: necessarily be removed after: applyingv one :coat'before 7 vention to use more than one coat of each of the three types. Thus, a heavier coating may be built up, if desired, in a stepwise manner, rather than applying all of one type of coating in a single treatment.

Resistance to low temperature is tested by subjecting the coated fabric to a temperature of 20 F. for 30 minutes and then folding the fabric at that temperature. Examination is then made for cracking or flaking.

Blocking is measured by folding a piece of the fabric over on itself, placing it between glass plates and loading with a l-pound weight. After 30 minutes at 180 F. and cooling for minutes, the folded fabric is pulled apart to note blocking. A piece which opens without any effort or noise is free of blocking. A crackling noise without visible picking or cohesion of the coating to itself is regarded as indicating slight blocking. Prior art coatings may block badly enough to coalesce.

Adhesion may be estimated by two tests. In the first, the coating is scrubbed vigorously over itself and the number of scrubbing motions necessary to rupture the film is noted. In the other, the coated fabric is torn, using a pull nearly parallel with the surface, and the edges of the tear observed. Ragged edges denote poor adhesion, while a coating which severs exactly with the tear is said to have good adhesion. Multiple coatings made according to the present invention have numerous advantages over the prior art, in that they are substantially noninfiammable as compared with nitrocellulose coatings; are designed to contain relatively large proportions of plasticizers in the wetting and toughening coats, but at the same time will not block or exude plasticizers, due to the presence of the sealing coat.

Wherever viscosity of ethyl cellulose is referred to throughout the examples, specification, and claims, it will be understood to mean centipoises viscosity in 80-20 toluene-alcohol mixtures measured at 25 C. containing 5% ethyl cellulose by weight.

What I claim and desire to protect by Letters Patent is:

l. A textile fabric bearing a flexible, nonblocking multiple coating comprising: a wetting coat comprising ethyl cellulose having an ethoxyl content between about 40.0 per cent and about 52.0

per cent by weight and a plasticizer, the ethyl cellulosezplasticizer ratio being in the range between about 1:1 and about 123.5, said wetting coat substantially closing the interstices of said fabric without forming a continuous coating thereon; a toughening coat comprising ethyl cellulose having an ethoxyl content between about 44.5 per cent and about 52.0 per cent by weight and a plasticizer, the ethyl cellulosezplasticizer ratio being in the range between about 3:1 and about 1:2 but substantially greater than that of the wetting coat composition; said toughening coat forming a continuous coating on the surface of said fabric and tightly adhering thereto with substantially no impregnation thereof; and a sealing coat superimposed upon the toughening coat and comprising an ethyl cellulose having an ethoxyl content between about 40.0 :per cent and about 45.5 per cent by weight, the ethoxyl content of the ethyl cellulose in said sealing coat being lower than the ethoxyl content of the ethyl cellulose in said toughening coat by at least 1.3 per cent, whereby substantial migration therethrough of the plasticizers of the wetting and toughening coats is prevented.

2. A textile fabric bearing coatings'according to claim 1, in which the plasticizer comprises chlorinated diphenyl.

3. A textile fabric bearing coatings to claim 1, in which the plasticizer raw castor oil.

4. A textile fabric bearing coatings to claim 1, in which the plasticizer bodied castor oil.

5. A textile fabric bearing coatings according to claim 1, in which the top coating contains a fiatting agent.

6. A textile fabric bearing coatings according to claim 1, in which the top coating contains zinc stearate.

7. A textile fabric bearing coatings according to claim 1, in which the ethyl celluloses which comprise the first two coatings have viscosities according comprises according comprises between about 50 and about 300 centipoises when measured at 25 C., in 5% solution of -20 toluene-alcohol.

8. A textile fabric bearing coatings according to claim 1, in which the ethyl cellulose which comprises the top coating has a viscosity between about and about 500 centipoises when measured at 25 C. in 5% solution of 80-20 toluene-alcohol.

- 9. A textile fabric bearing a flexible, nonblocking multiple coating comprising: a wetting coat comprising ethyl cellulose having an ethoxyl content between about 40.0 per cent and about 52.0 per cent by weight and a plasticizer, the ethyl cellulosez plasticizer ratio being in the range between about 1:23 and about 1:27, said wetting coat substantially closing the interstices of said fabric without forming a continuous coating thereon; a toughening coat comprising ethyl cellulose having an ethoxyl content between about 44.5 per cent and about 52.0 per cent by weight and a plasticizer, the ethyl cellulosezplasticizer ratio being in in the range between about 111 and about 111.5, said toughening coat forming a continuous coating on the surface of said fabric and tightly adhering thereto with substantially no impregnation thereof; and a sealing coat superimposed upon the toughening coat and comprising an ethyl cellulose having an ethoxyl content between about 40.0 per cent and about 45.5 per cent by weight, the ethoxyl content of the ethyl cellulose in said sealing coat being lower than the ethoxyl content of the ethyl cellulose in said toughening coat by at least 1.3 per cent, whereby substantial migration therethrough of the plasticizers of the wetting and toughening coats is prevented.

WILLIAM W. KOCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,244,567 Whitmore Oct. 30, 1917 1,521,055 Tesse Dec. 30, 1924 1,552,808 Sulzer Sept. 8, 1925 1,590,783 Tesse June 29, 1926 1,883,396 Moss Oct. 18, 1932 2,014,068 Hutchman Sept. 10, 1935 2,105,489 Moss Jan. 18, 1938 2,131,882 Armor et a1 Oct. 4, 1938 2,217,171 Kumnich et a1 Oct. 8, 1940 2,223,288 Lester Nov. 26, 1940 2,287,484 Pereny et al. June 23, 1942 

1. A TEXTILE FABRIC BEARING A FLEXIBLE, NONBLOCKING MULTIPLE COATING COMPRISING: A WETTING COAT COMPRISING ETHYL CELLULOSE HAVING AN ETHOXYL CONTENT BETWEEN ABOUT 40.0 PER CENT AND ABOUT 52.0 PER CENT BY WEIGHT AND A PLASTICIZER, THE ETHYL CELLULOSE: PLASTICIZER RATIO BEING IN THE RANGE BETWEEN ABOUT 1:1 AND ABOUT 1:3.5, SAID WETTING COAT SUBSTANTIALLY CLOSING THE INTERSTICES OF SAID FABRIC WITHOUT FORMING A CONTINUOUS COATING THEREON; A TOUGHENING COAT COMPRISING ETHYL CELLULOSE HAVING AN ETHOXYL CONTENT BETWEEN ABOUT 44.5 PER CENT AND ABUT 52.0 PER CENT BY WEIGHT AND A PLASTICIZER, THE ETHYL CELLULOSE:PLASTICIZER RATIO BEING IN THE RANGE BETWEEN ABOUT 3:1 AND ABOUT 1:2 BUT SUBTANTIALLY GREATER THAN THAT OF THE WETTING COAT COMPOSITION; SAID TOUGHENING COAT FORMING A CONTINUOUS COATING ON THE SURFACE OF SAID FABRIC AND TIGHTLY ADHERING THERETO WITH SUBSTANTIALLY NO IMPREGNATION THEREOF; AND A SEALING COAT SUPERIMPOSED UPON THE TOUGHENING COAT AND COMPRISING AN ETHYL CELLULOSE HAVING AN ETHOXYL CONTENT BETWEEN ABOUT 40.0 PER CENT AND ABOUT 45.5 PER CENT BY WEIGHT, THE ETHOXYL CONTENT OF THE ETHYL CELLULOSE IN SAID SEALING COAT BEING LOWER THAN THE ETHOXYL CONTENT OF THE ETHYL CELLULOSE IN SAID TOUGHENING COAT BY AT LEAST 1.3 PER CENT, WHEREBY SUBSTANTIAL MIGRATION THERETHROUGH OF THE PLASTICIZERS OF THE WETTING AND TOUGHENING COATS IS PREVENTED. 